diff --git a/.gitignore b/.gitignore
index 5148db3022..a3f5d94252 100644
--- a/.gitignore
+++ b/.gitignore
@@ -9,3 +9,4 @@ Factor/factor
 *.lib
 *.image
 *.dylib
+factor
diff --git a/Factor.app/Contents/MacOS/.dummy b/Factor.app/Contents/MacOS/.dummy
new file mode 100644
index 0000000000..e69de29bb2
diff --git a/Makefile b/Makefile
index 73c7b2eb5e..c5db03896e 100644
--- a/Makefile
+++ b/Makefile
@@ -44,21 +44,20 @@ EXE_OBJS = $(PLAF_EXE_OBJS)
 default:
 	@echo "Run 'make' with one of the following parameters:"
 	@echo ""
-	@echo "freebsd-x86"
-	@echo "freebsd-amd64"
-	@echo "linux-x86"
-	@echo "linux-amd64"
+	@echo "freebsd-x86-32"
+	@echo "freebsd-x86-64"
+	@echo "linux-x86-32"
+	@echo "linux-x86-64"
 	@echo "linux-ppc"
 	@echo "linux-arm"
-	@echo "openbsd-x86"
-	@echo "openbsd-amd64"
-	@echo "macosx-x86"
+	@echo "openbsd-x86-32"
+	@echo "openbsd-x86-64"
+	@echo "macosx-x86-32"
 	@echo "macosx-ppc"
-	@echo "solaris-x86"
-	@echo "solaris-amd64"
+	@echo "solaris-x86-32"
+	@echo "solaris-x86-64"
 	@echo "windows-ce-arm"
-	@echo "windows-ce-x86"
-	@echo "windows-nt-x86"
+	@echo "windows-nt-x86-32"
 	@echo ""
 	@echo "Additional modifiers:"
 	@echo ""
@@ -67,17 +66,17 @@ default:
 	@echo "NO_UI=1  don't link with X11 libraries (ignored on Mac OS X)"
 	@echo "X11=1  force link with X11 libraries instead of Cocoa (only on Mac OS X)"
 
-openbsd-x86:
-	$(MAKE) $(EXECUTABLE) CONFIG=vm/Config.openbsd.x86
+openbsd-x86-32:
+	$(MAKE) $(EXECUTABLE) CONFIG=vm/Config.openbsd.x86.32
 
-openbsd-amd64:
-	$(MAKE) $(EXECUTABLE) CONFIG=vm/Config.openbsd.amd64
+openbsd-x86-64:
+	$(MAKE) $(EXECUTABLE) CONFIG=vm/Config.openbsd.x86.64
 
-freebsd-x86:
-	$(MAKE) $(EXECUTABLE) CONFIG=vm/Config.freebsd.x86
+freebsd-x86-32:
+	$(MAKE) $(EXECUTABLE) CONFIG=vm/Config.freebsd.x86.32
 
-freebsd-amd64:
-	$(MAKE) $(EXECUTABLE) CONFIG=vm/Config.freebsd.amd64
+freebsd-x86-64:
+	$(MAKE) $(EXECUTABLE) CONFIG=vm/Config.freebsd.x86.64
 
 macosx-freetype:
 	ln -sf libfreetype.6.dylib \
@@ -86,14 +85,14 @@ macosx-freetype:
 macosx-ppc: macosx-freetype
 	$(MAKE) $(EXECUTABLE) macosx.app CONFIG=vm/Config.macosx.ppc
 
-macosx-x86: macosx-freetype
-	$(MAKE) $(EXECUTABLE) macosx.app CONFIG=vm/Config.macosx.x86
+macosx-x86-32: macosx-freetype
+	$(MAKE) $(EXECUTABLE) macosx.app CONFIG=vm/Config.macosx.x86.32
 
-linux-x86:
-	$(MAKE) $(EXECUTABLE) CONFIG=vm/Config.linux.x86
+linux-x86-32:
+	$(MAKE) $(EXECUTABLE) CONFIG=vm/Config.linux.x86.32
 
-linux-amd64:
-	$(MAKE) $(EXECUTABLE) CONFIG=vm/Config.linux.amd64
+linux-x86-64:
+	$(MAKE) $(EXECUTABLE) CONFIG=vm/Config.linux.x86.64
 
 linux-ppc:
 	$(MAKE) $(EXECUTABLE) CONFIG=vm/Config.linux.ppc
@@ -101,21 +100,18 @@ linux-ppc:
 linux-arm:
 	$(MAKE) $(EXECUTABLE) CONFIG=vm/Config.linux.arm
 
-solaris-x86:
-	$(MAKE) $(EXECUTABLE) CONFIG=vm/Config.solaris.x86
+solaris-x86-32:
+	$(MAKE) $(EXECUTABLE) CONFIG=vm/Config.solaris.x86.32
 
-solaris-amd64:
-	$(MAKE) $(EXECUTABLE) CONFIG=vm/Config.solaris.amd64
+solaris-x86-64:
+	$(MAKE) $(EXECUTABLE) CONFIG=vm/Config.solaris.x86.64
 
-windows-nt-x86:
-	$(MAKE) $(EXECUTABLE) CONFIG=vm/Config.windows.nt.x86
+windows-nt-x86-32:
+	$(MAKE) $(EXECUTABLE) CONFIG=vm/Config.windows.nt.x86.32
 
 windows-ce-arm:
 	$(MAKE) $(EXECUTABLE) CONFIG=vm/Config.windows.ce.arm
 
-windows-ce-x86:
-	$(MAKE) $(EXECUTABLE) CONFIG=vm/Config.windows.ce.x86
-
 macosx.app: factor
 	mkdir -p $(BUNDLE)/Contents/MacOS
 	cp $(EXECUTABLE) $(BUNDLE)/Contents/MacOS/factor
diff --git a/core/bootstrap/image/image.factor b/core/bootstrap/image/image.factor
index 36d2f7f1de..0f61eb4c83 100644
--- a/core/bootstrap/image/image.factor
+++ b/core/bootstrap/image/image.factor
@@ -32,7 +32,7 @@ IN: bootstrap.image
 : -1-offset             9 ; inline
 
 : array-start 2 bootstrap-cells object tag-number - ;
-: scan@ array-start 4 - ;
+: scan@ array-start bootstrap-cell - ;
 : wrapper@ bootstrap-cell object tag-number - ;
 : word-xt@ 8 bootstrap-cells object tag-number - ;
 : quot-array@ bootstrap-cell object tag-number - ;
diff --git a/core/cpu/x86/32/32.factor b/core/cpu/x86/32/32.factor
index 998e87c7a0..4ef7777dd4 100644
--- a/core/cpu/x86/32/32.factor
+++ b/core/cpu/x86/32/32.factor
@@ -206,10 +206,10 @@ M: x86-backend %box-small-struct ( size -- )
 
 M: x86-backend %prepare-alien-indirect ( -- )
     "unbox_alien" f %alien-invoke
-    ESP cell temp@ [+] EAX MOV ;
+    cell temp@ EAX MOV ;
 
 M: x86-backend %alien-indirect ( -- )
-    ESP cell temp@ [+] CALL ;
+    cell temp@ CALL ;
 
 M: x86-backend %alien-callback ( quot -- )
     4 [
diff --git a/core/cpu/x86/32/bootstrap.factor b/core/cpu/x86/32/bootstrap.factor
index f9504f50c7..289ae0c213 100644
--- a/core/cpu/x86/32/bootstrap.factor
+++ b/core/cpu/x86/32/bootstrap.factor
@@ -1,106 +1,18 @@
 ! Copyright (C) 2007 Slava Pestov.
 ! See http://factorcode.org/license.txt for BSD license.
 USING: bootstrap.image.private kernel namespaces system
-cpu.x86.assembler layouts vocabs ;
-IN: bootstrap.x86.32
+cpu.x86.assembler layouts vocabs parser ;
+IN: bootstrap.x86
 
 4 \ cell set
-big-endian off
-
-1 jit-code-format set
 
+: arg0 EAX ;
+: arg1 EDX ;
+: stack-reg ESP ;
 : ds-reg ESI ;
 : scan-reg EBX ;
 : xt-reg ECX ;
-: scan-save ESP 12 [+] ;
+: fixnum>slot@ arg0 1 SAR ;
+: next-frame@ -44 ;
 
-[
-    EAX EAX quot-array@ [+] MOV             ! load array
-    scan-reg EAX 1 [+] LEA                  ! initialize scan pointer
-] { } make jit-setup set
-
-[
-    xt-reg PUSH                             ! save XT
-    xt-reg ESP -44 [+] LEA                  ! compute forward chain pointer
-    xt-reg PUSH                             ! save forward chain pointer
-    EAX PUSH                                ! save array
-    ESP 16 SUB                              ! reserve space for scan-save
-] { } make jit-prolog set
-
-: advance-scan scan-reg 4 ADD ;
-
-[
-    advance-scan
-    ds-reg 4 ADD                            ! increment datastack pointer
-    EAX scan-reg [] MOV                     ! load literal
-    ds-reg [] EAX MOV                       ! store literal on datastack
-] { } make jit-push-literal set
-
-[
-    advance-scan
-    ds-reg 4 ADD                            ! increment datastack pointer
-    EAX scan-reg [] MOV                     ! load wrapper
-    EAX dup wrapper@ [+] MOV                ! load wrapper-obj slot
-    ds-reg [] EAX MOV                       ! store literal on datastack
-] { } make jit-push-wrapper set
-
-[
-    EDX ESP MOV                             ! pass callstack pointer as arg 2
-] { } make jit-word-primitive-jump set
-
-[
-    EDX ESP -4 [+] LEA                      ! pass callstack pointer as arg 2
-] { } make jit-word-primitive-call set
-
-[
-    EAX scan-reg 4 [+] MOV                  ! load word
-    EAX word-xt@ [+] JMP                    ! jump to word XT
-] { } make jit-word-jump set
-
-[
-    advance-scan
-    scan-save scan-reg MOV                  ! save scan pointer
-    EAX scan-reg [] MOV                     ! load word
-    EAX word-xt@ [+] CALL                   ! call word XT
-    scan-reg scan-save MOV                  ! restore scan pointer
-] { } make jit-word-call set
-
-: load-branch
-    EAX ds-reg [] MOV                       ! load boolean
-    ds-reg 4 SUB                            ! pop boolean
-    EAX \ f tag-number CMP                  ! compare it with f
-    EAX scan-reg 8 [+] CMOVE                ! load false branch if equal
-    EAX scan-reg 4 [+] CMOVNE               ! load true branch if not equal
-    scan-reg 12 ADD                         ! advance scan pointer
-    xt-reg EAX quot-xt@ [+] MOV             ! load quotation-xt
-    ;
-
-[
-    load-branch
-    xt-reg JMP
-] { } make jit-if-jump set
-
-[
-    load-branch
-    ESP [] scan-reg MOV                     ! save scan pointer
-    xt-reg CALL                             ! call quotation
-    scan-reg ESP [] MOV                     ! restore scan pointer
-] { } make jit-if-call set
-
-[
-    EAX ds-reg [] MOV                       ! load index
-    EAX 1 SAR                               ! turn it into an array offset
-    ds-reg 4 SUB                            ! pop index
-    EAX scan-reg 4 [+] ADD                  ! compute quotation location
-    EAX EAX array-start [+] MOV             ! load quotation
-    xt-reg EAX quot-xt@ [+] MOV             ! load quotation-xt
-    xt-reg JMP                              ! execute quotation
-] { } make jit-dispatch set
-
-[
-    ESP 28 ADD                              ! unwind stack frame
-] { } make jit-epilog set
-
-[ 0 RET ] { } make jit-return set
-
-"bootstrap.x86.32" forget-vocab
+"resource:core/cpu/x86/bootstrap.factor" run-file
diff --git a/core/cpu/x86/64/64.factor b/core/cpu/x86/64/64.factor
index 1625a563f2..708c75e0bd 100644
--- a/core/cpu/x86/64/64.factor
+++ b/core/cpu/x86/64/64.factor
@@ -13,11 +13,13 @@ PREDICATE: x86-backend amd64-backend
 M: amd64-backend ds-reg R14 ;
 M: amd64-backend rs-reg R15 ;
 M: amd64-backend stack-reg RSP ;
+M: x86-backend xt-reg RCX ;
+M: x86-backend stack-save-reg RSI ;
 
-M: temp-reg v>operand drop R11 ;
+M: temp-reg v>operand drop RBX ;
 
 M: int-regs return-reg drop RAX ;
-M: int-regs vregs drop { RAX RCX RDX RSI RDI RBP R8 R9 R10 } ;
+M: int-regs vregs drop { RAX RCX RDX RBP RSI RDI R8 R9 R10 R11 R12 R13 } ;
 M: int-regs param-regs drop { RDI RSI RDX RCX R8 R9 } ;
 
 M: float-regs return-reg drop XMM0 ;
@@ -144,17 +146,17 @@ M: amd64-backend %alien-indirect ( -- )
     cell temp@ CALL ;
 
 M: amd64-backend %alien-callback ( quot -- )
-    RDI load-indirect "run_callback" f compile-c-call ;
+    RDI load-indirect "c_to_factor" f compile-c-call ;
 
 M: amd64-backend %callback-value ( ctype -- )
     ! Save top of data stack
     %prepare-unbox
     ! Put former top of data stack in RDI
-    temp@ RDI MOV
+    cell temp@ RDI MOV
     ! Restore data/call/retain stacks
     "unnest_stacks" f %alien-invoke
     ! Put former top of data stack in RDI
-    RDI temp@ MOV
+    RDI cell temp@ MOV
     ! Unbox former top of data stack to return registers
     unbox-return ;
 
diff --git a/core/cpu/x86/64/bootstrap.factor b/core/cpu/x86/64/bootstrap.factor
index bccdcbd7f1..00db1ac119 100644
--- a/core/cpu/x86/64/bootstrap.factor
+++ b/core/cpu/x86/64/bootstrap.factor
@@ -1,4 +1,18 @@
-USING: bootstrap.image.private kernel namespaces system ;
+! Copyright (C) 2007 Slava Pestov.
+! See http://factorcode.org/license.txt for BSD license.
+USING: bootstrap.image.private kernel namespaces system
+cpu.x86.assembler layouts vocabs parser ;
+IN: bootstrap.x86
 
 8 \ cell set
-big-endian off
+
+: arg0 RDI ;
+: arg1 RSI ;
+: stack-reg RSP ;
+: ds-reg R14 ;
+: scan-reg RBX ;
+: xt-reg RCX ;
+: fixnum>slot@ ;
+: next-frame@ -88 ;
+
+"resource:core/cpu/x86/bootstrap.factor" run-file
diff --git a/core/cpu/x86/architecture/architecture.factor b/core/cpu/x86/architecture/architecture.factor
index 6879e23051..91e8bf1460 100644
--- a/core/cpu/x86/architecture/architecture.factor
+++ b/core/cpu/x86/architecture/architecture.factor
@@ -150,13 +150,13 @@ M: x86-backend small-enough? ( n -- ? )
 
 : %tag-fixnum ( reg -- ) tag-bits get SHL ;
 
-: temp@ \ stack-frame get swap - ;
+: temp@ stack-reg \ stack-frame get rot - [+] ;
 
 : struct-return@ ( size n -- n )
     [
         stack-frame* cell + +
     ] [
-        temp@
+        \ stack-frame get swap -
     ] ?if ;
 
 HOOK: %unbox-struct-1 compiler-backend ( -- )
diff --git a/core/cpu/x86/bootstrap.factor b/core/cpu/x86/bootstrap.factor
new file mode 100644
index 0000000000..67156d8300
--- /dev/null
+++ b/core/cpu/x86/bootstrap.factor
@@ -0,0 +1,102 @@
+! Copyright (C) 2007 Slava Pestov.
+! See http://factorcode.org/license.txt for BSD license.
+USING: bootstrap.image.private kernel namespaces system
+cpu.x86.assembler layouts vocabs math ;
+IN: bootstrap.x86
+
+big-endian off
+
+1 jit-code-format set
+
+: scan-save stack-reg 3 bootstrap-cells [+] ;
+
+[
+    arg0 arg0 quot-array@ [+] MOV              ! load array
+    scan-reg arg0 scan@ [+] LEA                ! initialize scan pointer
+] { } make jit-setup set                       
+                                               
+[                                              
+    xt-reg PUSH                                ! save XT
+    xt-reg stack-reg next-frame@ [+] LEA       ! compute forward chain pointer
+    xt-reg PUSH                                ! save forward chain pointer
+    arg0 PUSH                                  ! save array
+    stack-reg 4 bootstrap-cells SUB            ! reserve space for scan-save
+] { } make jit-prolog set                      
+                                               
+: advance-scan scan-reg bootstrap-cell ADD ;   
+                                               
+[                                              
+    advance-scan                               
+    ds-reg bootstrap-cell ADD                  ! increment datastack pointer
+    arg0 scan-reg [] MOV                       ! load literal
+    ds-reg [] arg0 MOV                         ! store literal on datastack
+] { } make jit-push-literal set                
+                                               
+[                                              
+    advance-scan                               
+    ds-reg bootstrap-cell ADD                  ! increment datastack pointer
+    arg0 scan-reg [] MOV                       ! load wrapper
+    arg0 dup wrapper@ [+] MOV                  ! load wrapper-obj slot
+    ds-reg [] arg0 MOV                         ! store literal on datastack
+] { } make jit-push-wrapper set                
+                                               
+[                                              
+    arg1 stack-reg MOV                         ! pass callstack pointer as arg 2
+] { } make jit-word-primitive-jump set         
+                                               
+[                                              
+    arg1 stack-reg bootstrap-cell neg [+] LEA  ! pass callstack pointer as arg 2
+] { } make jit-word-primitive-call set         
+                                               
+[                                              
+    arg0 scan-reg bootstrap-cell [+] MOV       ! load word
+    arg0 word-xt@ [+] JMP                      ! jump to word XT
+] { } make jit-word-jump set                   
+                                               
+[                                              
+    advance-scan                               
+    scan-save scan-reg MOV                     ! save scan pointer
+    arg0 scan-reg [] MOV                       ! load word
+    arg0 word-xt@ [+] CALL                     ! call word XT
+    scan-reg scan-save MOV                     ! restore scan pointer
+] { } make jit-word-call set                   
+                                               
+: load-branch                                  
+    arg0 ds-reg [] MOV                         ! load boolean
+    ds-reg bootstrap-cell SUB                  ! pop boolean
+    arg0 \ f tag-number CMP                    ! compare it with f
+    arg0 scan-reg 2 bootstrap-cells [+] CMOVE  ! load false branch if equal
+    arg0 scan-reg 1 bootstrap-cells [+] CMOVNE ! load true branch if not equal
+    scan-reg 3 bootstrap-cells ADD             ! advance scan pointer
+    xt-reg arg0 quot-xt@ [+] MOV               ! load quotation-xt
+    ;
+
+[
+    load-branch
+    xt-reg JMP
+] { } make jit-if-jump set
+
+[
+    load-branch
+    stack-reg [] scan-reg MOV                  ! save scan pointer
+    xt-reg CALL                                ! call quotation
+    scan-reg stack-reg [] MOV                  ! restore scan pointer
+] { } make jit-if-call set
+
+[
+    arg0 ds-reg [] MOV                         ! load index
+    fixnum>slot@                               ! turn it into an array offset
+    ds-reg bootstrap-cell SUB                  ! pop index
+    arg0 scan-reg bootstrap-cell [+] ADD       ! compute quotation location
+    arg0 arg0 array-start [+] MOV              ! load quotation
+    xt-reg arg0 quot-xt@ [+] MOV               ! load quotation-xt
+    xt-reg JMP                                 ! execute quotation
+] { } make jit-dispatch set
+
+[
+    stack-reg 7 bootstrap-cells ADD            ! unwind stack frame
+] { } make jit-epilog set
+
+[ 0 RET ] { } make jit-return set
+
+"bootstrap.x86" forget-vocab
diff --git a/core/cpu/x86/intrinsics/intrinsics.factor b/core/cpu/x86/intrinsics/intrinsics.factor
index fc4d7388bf..0228848a33 100644
--- a/core/cpu/x86/intrinsics/intrinsics.factor
+++ b/core/cpu/x86/intrinsics/intrinsics.factor
@@ -71,29 +71,38 @@ IN: cpu.x86.intrinsics
 } define-intrinsic
 
 ! Slots
+: %slot-literal-known-tag
+    "obj" operand
+    "n" get cells
+    "obj" operand-tag - [+] ;
+
+: %slot-literal-any-tag
+    "obj" operand %untag
+    "obj" operand "n" get cells [+] ;
+
+: %slot-any
+    "obj" operand %untag
+    "n" operand fixnum>slot@
+    "obj" operand "n" operand [+] ;
 
 \ slot {
+    ! Slot number is literal and the tag is known
+    {
+        [ "obj" operand %slot-literal-known-tag MOV ] H{
+            { +input+ { { f "obj" known-tag } { [ small-slot? ] "n" } } }
+            { +output+ { "obj" } }
+        }
+    }
     ! Slot number is literal
     {
-        [
-            "obj" operand %untag
-            ! load slot value
-            "obj" operand dup "n" get cells [+] MOV
-        ] H{
+        [ "obj" operand %slot-literal-any-tag MOV ] H{
             { +input+ { { f "obj" } { [ small-slot? ] "n" } } }
             { +output+ { "obj" } }
         }
     }
     ! Slot number in a register
     {
-        [
-            "obj" operand %untag
-            ! turn tagged fixnum slot # into an offset,
-            ! multiple of 4
-            "n" operand fixnum>slot@
-            ! load slot value
-            "obj" operand dup "n" operand [+] MOV
-        ] H{
+        [ "obj" operand %slot-any MOV ] H{
             { +input+ { { f "obj" } { f "n" } } }
             { +output+ { "obj" } }
             { +clobber+ { "n" } }
@@ -105,38 +114,28 @@ IN: cpu.x86.intrinsics
     #! Mark the card pointed to by vreg.
     "val" operand-immediate? "obj" get fresh-object? or [
         "obj" operand card-bits SHR
-        "scratch" operand HEX: ffffffff MOV
-        "cards_offset" f rc-absolute-cell rel-dlsym
-        "scratch" operand dup [] MOV
-        "scratch" operand "obj" operand [+] card-mark OR
+        "cards_offset" f %alien-global
+        temp-reg v>operand "obj" operand [+] card-mark OR
     ] unless ;
 
 \ set-slot {
+    ! Slot number is literal and the tag is known
+    {
+        [ %slot-literal-known-tag "val" operand MOV generate-write-barrier ] H{
+            { +input+ { { f "val" } { f "obj" known-tag } { [ small-slot? ] "n" } } }
+            { +clobber+ { "obj" } }
+        }
+    }
     ! Slot number is literal
     {
-        [
-            "obj" operand %untag
-            ! store new slot value
-            "obj" operand "n" get cells [+] "val" operand MOV
-            generate-write-barrier
-        ] H{
+        [ %slot-literal-any-tag "val" operand MOV generate-write-barrier ] H{
             { +input+ { { f "val" } { f "obj" } { [ small-slot? ] "n" } } }
-            { +scratch+ { { f "scratch" } } }
             { +clobber+ { "obj" } }
         }
     }
     ! Slot number in a register
     {
-        [
-            ! turn tagged fixnum slot # into an offset
-            "n" operand fixnum>slot@
-            "obj" operand %untag
-            ! store new slot value
-            "obj" operand "n" operand [+] "val" operand MOV
-            ! reuse register
-            "n" get "scratch" set
-            generate-write-barrier
-        ] H{
+        [ %slot-any "val" operand MOV generate-write-barrier ] H{
             { +input+ { { f "val" } { f "obj" } { f "n" } } }
             { +clobber+ { "obj" "n" } }
         }
diff --git a/extra/factory/factory-menus b/extra/factory/factory-menus
index 94b249a806..768906029c 100644
--- a/extra/factory/factory-menus
+++ b/extra/factory/factory-menus
@@ -1,7 +1,8 @@
 ! -*-factor-*-
 
 USING: kernel unix vars mortar slot-accessors
-       x.widgets.wm.menu x.widgets.wm.unmapped-frames-menu ;
+       x.widgets.wm.menu x.widgets.wm.unmapped-frames-menu
+       factory.commands factory.load ;
 
 IN: factory
 
diff --git a/extra/factory/factory-rc b/extra/factory/factory-rc
index 6a0c31d4c5..6d46c07a2a 100644
--- a/extra/factory/factory-rc
+++ b/extra/factory/factory-rc
@@ -4,6 +4,7 @@ USING: kernel mortar x
        x.widgets.wm.root
        x.widgets.wm.workspace
        x.widgets.wm.unmapped-frames-menu
+       factory.load
        tty-server ;
 
 IN: factory
diff --git a/extra/http/server/responders/responders.factor b/extra/http/server/responders/responders.factor
index b13239ac55..725cb515b0 100644
--- a/extra/http/server/responders/responders.factor
+++ b/extra/http/server/responders/responders.factor
@@ -126,13 +126,7 @@ SYMBOL: max-post-request
     #! Add a responder object to the list.
     "responder" over at  responders get set-at ;
 
-: add-simple-responder ( name quot -- )
-    [
-        [ drop ] swap append dup "get" set "post" set
-        "responder" set
-    ] H{ } make-assoc add-responder ;
-
-: make-responder ( quot -- responder )
+: make-responder ( quot -- )
     #! quot has stack effect ( url -- )
     [
         [
@@ -151,6 +145,12 @@ SYMBOL: max-post-request
         call
     ] H{ } make-assoc add-responder ;
 
+: add-simple-responder ( name quot -- )
+    [
+        [ drop ] swap append dup "get" set "post" set
+        "responder" set
+    ] make-responder ;
+
 : vhost ( name -- vhost )
     vhosts get at [ "default" vhost ] unless* ;
 
@@ -175,7 +175,7 @@ SYMBOL: max-post-request
     "/" ?head drop ;
 
 : serve-explicit-responder ( method url -- )
-    "/" split1 
+    "/" split1
     "/responder/" pick "/" 3append "responder-url" set
     dup [
         swap responder call-responder
@@ -200,7 +200,7 @@ SYMBOL: max-post-request
     "404 No such responder" httpd-error ;
 
 ! create a responders hash if it doesn't already exist
-global [ 
+global [
     responders [ H{ } assoc-like ] change
     
     ! 404 error message pages are served by this guy
diff --git a/extra/io/unix/launcher/launcher.factor b/extra/io/unix/launcher/launcher.factor
index c3fe6d0a05..7b286feae1 100644
--- a/extra/io/unix/launcher/launcher.factor
+++ b/extra/io/unix/launcher/launcher.factor
@@ -9,16 +9,15 @@ USE: unix
 : with-fork ( quot -- pid )
     fork [ zero? -rot if ] keep ; inline
 
-: prepare-execve ( args -- cmd args envp )
+: prepare-execvp ( args -- cmd args )
     #! Doesn't free any memory, so we only call this word
     #! after forking.
     [ malloc-char-string ] map
     [ first ] keep
-    f add >c-void*-array
-    f ;
+    f add >c-void*-array ;
 
 : (spawn-process) ( args -- )
-    [ prepare-execve execve ] catch 1 exit ;
+    [ prepare-execvp execvp ] catch 1 exit ;
 
 : spawn-process ( args -- pid )
     [ (spawn-process) ] [ drop ] with-fork ;
diff --git a/extra/json/writer/writer.factor b/extra/json/writer/writer.factor
index fc11904890..4370a38411 100644
--- a/extra/json/writer/writer.factor
+++ b/extra/json/writer/writer.factor
@@ -21,6 +21,11 @@ M: string json-print ( obj -- )
 M: number json-print ( num -- )  
   number>string write ;
 
+! sequence and number overlap, we provide an explicit
+! disambiguation method
+M: integer json-print ( num -- )  
+  number>string write ;
+
 M: sequence json-print ( array -- string ) 
   CHAR: [ write1 [ >json ] map "," join write CHAR: ] write1 ;
 
diff --git a/extra/unix/unix.factor b/extra/unix/unix.factor
index 8eb940352f..ca4b569587 100644
--- a/extra/unix/unix.factor
+++ b/extra/unix/unix.factor
@@ -107,6 +107,7 @@ FUNCTION: void close ( int fd ) ;
 FUNCTION: int connect ( int s, void* name, socklen_t namelen ) ;
 FUNCTION: int dup2 ( int oldd, int newd ) ;
 ! FUNCTION: int dup ( int oldd ) ;
+FUNCTION: int execvp ( char* path, char** argv ) ;
 FUNCTION: int execve ( char* path, char** argv, char** envp ) ;
 FUNCTION: int fchdir ( int fd ) ;
 FUNCTION: int fchmod ( int fd, mode_t mode ) ;
diff --git a/vm/Config.amd64 b/vm/Config.amd64
deleted file mode 100644
index d2c706cf14..0000000000
--- a/vm/Config.amd64
+++ /dev/null
@@ -1,2 +0,0 @@
-BOOT_ARCH = amd64
-PLAF_DLL_OBJS += vm/cpu-amd64.o
diff --git a/vm/Config.arm b/vm/Config.arm
index fc41bb9c37..2273d61caf 100644
--- a/vm/Config.arm
+++ b/vm/Config.arm
@@ -1,2 +1 @@
-BOOT_ARCH = arm
 PLAF_DLL_OBJS += vm/cpu-arm.o
diff --git a/vm/Config.freebsd.amd64 b/vm/Config.freebsd.x86.32
similarity index 50%
rename from vm/Config.freebsd.amd64
rename to vm/Config.freebsd.x86.32
index db6f9f3c1e..969ba1cea6 100644
--- a/vm/Config.freebsd.amd64
+++ b/vm/Config.freebsd.x86.32
@@ -1,2 +1,2 @@
 include vm/Config.freebsd
-include vm/Config.amd64
+include vm/Config.x86.32
diff --git a/vm/Config.freebsd.x86 b/vm/Config.freebsd.x86.64
similarity index 50%
rename from vm/Config.freebsd.x86
rename to vm/Config.freebsd.x86.64
index 1273130dc7..0f9667e48d 100644
--- a/vm/Config.freebsd.x86
+++ b/vm/Config.freebsd.x86.64
@@ -1,2 +1,2 @@
 include vm/Config.freebsd
-include vm/Config.x86
+include vm/Config.x86.64
diff --git a/vm/Config.linux.x86 b/vm/Config.linux.x86
deleted file mode 100644
index 313b999133..0000000000
--- a/vm/Config.linux.x86
+++ /dev/null
@@ -1,2 +0,0 @@
-include vm/Config.linux
-include vm/Config.x86
diff --git a/vm/Config.linux.x86.32 b/vm/Config.linux.x86.32
new file mode 100644
index 0000000000..7f4f3b4bfe
--- /dev/null
+++ b/vm/Config.linux.x86.32
@@ -0,0 +1,2 @@
+include vm/Config.linux
+include vm/Config.x86.32
diff --git a/vm/Config.linux.amd64 b/vm/Config.linux.x86.64
similarity index 73%
rename from vm/Config.linux.amd64
rename to vm/Config.linux.x86.64
index d7ae032e6a..bfd1222496 100644
--- a/vm/Config.linux.amd64
+++ b/vm/Config.linux.x86.64
@@ -1,3 +1,3 @@
 include vm/Config.linux
-include vm/Config.amd64
+include vm/Config.x86.64
 LIBPATH = -L/usr/X11R6/lib64 -L/usr/X11R6/lib
diff --git a/vm/Config.macosx.x86 b/vm/Config.macosx.x86.32
similarity index 50%
rename from vm/Config.macosx.x86
rename to vm/Config.macosx.x86.32
index 27c47fcb63..5c0d4e0ede 100644
--- a/vm/Config.macosx.x86
+++ b/vm/Config.macosx.x86.32
@@ -1,2 +1,2 @@
 include vm/Config.macosx
-include vm/Config.x86
+include vm/Config.x86.32
diff --git a/vm/Config.openbsd.amd64 b/vm/Config.openbsd.x86.32
similarity index 50%
rename from vm/Config.openbsd.amd64
rename to vm/Config.openbsd.x86.32
index e895d34307..407083d38e 100644
--- a/vm/Config.openbsd.amd64
+++ b/vm/Config.openbsd.x86.32
@@ -1,2 +1,2 @@
 include vm/Config.openbsd
-include vm/Config.amd64
+include vm/Config.x86.32
diff --git a/vm/Config.openbsd.x86 b/vm/Config.openbsd.x86.64
similarity index 50%
rename from vm/Config.openbsd.x86
rename to vm/Config.openbsd.x86.64
index 99cf991032..d254e61bf8 100644
--- a/vm/Config.openbsd.x86
+++ b/vm/Config.openbsd.x86.64
@@ -1,2 +1,2 @@
 include vm/Config.openbsd
-include vm/Config.x86
+include vm/Config.x86.64
diff --git a/vm/Config.ppc b/vm/Config.ppc
index 3fa5fd8df1..1ded04dda1 100644
--- a/vm/Config.ppc
+++ b/vm/Config.ppc
@@ -1,2 +1 @@
-BOOT_ARCH = ppc
 PLAF_DLL_OBJS += vm/cpu-ppc.o
diff --git a/vm/Config.solaris.amd64 b/vm/Config.solaris.x86.32
similarity index 50%
rename from vm/Config.solaris.amd64
rename to vm/Config.solaris.x86.32
index 58bd2b2f4d..ffe59be468 100644
--- a/vm/Config.solaris.amd64
+++ b/vm/Config.solaris.x86.32
@@ -1,2 +1,2 @@
 include vm/Config.solaris
-include vm/Config.amd64
+include vm/Config.x86.32
diff --git a/vm/Config.solaris.x86 b/vm/Config.solaris.x86.64
similarity index 50%
rename from vm/Config.solaris.x86
rename to vm/Config.solaris.x86.64
index d839047c77..116725daed 100644
--- a/vm/Config.solaris.x86
+++ b/vm/Config.solaris.x86.64
@@ -1,2 +1,2 @@
 include vm/Config.solaris
-include vm/Config.x86
+include vm/Config.x86.64
diff --git a/vm/Config.windows.ce.x86 b/vm/Config.windows.ce.x86
deleted file mode 100644
index 0d1f776169..0000000000
--- a/vm/Config.windows.ce.x86
+++ /dev/null
@@ -1,2 +0,0 @@
-#CC = x86-wince-mingw32ce-gcc
-include vm/Config.windows.ce vm/Config.x86
diff --git a/vm/Config.windows.nt.x86 b/vm/Config.windows.nt.x86.32
similarity index 77%
rename from vm/Config.windows.nt.x86
rename to vm/Config.windows.nt.x86.32
index 8834332442..adc69b1e27 100644
--- a/vm/Config.windows.nt.x86
+++ b/vm/Config.windows.nt.x86.32
@@ -4,4 +4,4 @@ DLL_SUFFIX=-nt
 PLAF_DLL_OBJS += vm/os-windows-nt.o
 PLAF_EXE_OBJS += vm/resources.o
 PLAF_EXE_OBJS += vm/main-windows-nt.o
-include vm/Config.x86 vm/Config.windows
+include vm/Config.x86.32 vm/Config.windows
diff --git a/vm/Config.x86 b/vm/Config.x86.32
similarity index 75%
rename from vm/Config.x86
rename to vm/Config.x86.32
index bd739d3a85..bbd26e8e11 100644
--- a/vm/Config.x86
+++ b/vm/Config.x86.32
@@ -1,5 +1,5 @@
 BOOT_ARCH = x86
-PLAF_DLL_OBJS += vm/cpu-x86.o
+PLAF_DLL_OBJS += vm/cpu-x86.32.o
 
 # gcc bug workaround
 CFLAGS += -fno-builtin-strlen -fno-builtin-strcat -mtune=pentium4
diff --git a/vm/Config.x86.64 b/vm/Config.x86.64
new file mode 100644
index 0000000000..53a4d3c5e1
--- /dev/null
+++ b/vm/Config.x86.64
@@ -0,0 +1 @@
+PLAF_DLL_OBJS += vm/cpu-x86.64.o
diff --git a/vm/cpu-amd64.S b/vm/cpu-amd64.S
deleted file mode 100644
index 5df8bd0bf4..0000000000
--- a/vm/cpu-amd64.S
+++ /dev/null
@@ -1,8 +0,0 @@
-#include "asm.h"
-
-/* Callable from C as
-void *native_stack_pointer(void) */
-	.globl MANGLE(native_stack_pointer)
-MANGLE(native_stack_pointer):
-	mov %rsp,%rax
-	ret
diff --git a/vm/cpu-amd64.h b/vm/cpu-amd64.h
deleted file mode 100644
index 64d2c3a14a..0000000000
--- a/vm/cpu-amd64.h
+++ /dev/null
@@ -1,20 +0,0 @@
-#define FACTOR_CPU_STRING "x86.64"
-
-register CELL ds asm("r14");
-register CELL rs asm("r15");
-void **primitives;
-
-INLINE void flush_icache(CELL start, CELL len) {}
-
-void *native_stack_pointer(void);
-
-typedef CELL F_COMPILED_FRAME;
-
-#define PREVIOUS_FRAME(frame) (frame + 1)
-#define RETURN_ADDRESS(frame) (*(frame))
-
-INLINE void execute(CELL word)
-{
-	F_WORD *untagged = untag_object(word);
-	untagged->xt(word);
-}
diff --git a/vm/cpu-x86.32.S b/vm/cpu-x86.32.S
new file mode 100644
index 0000000000..19a735ec88
--- /dev/null
+++ b/vm/cpu-x86.32.S
@@ -0,0 +1,45 @@
+#include "asm.h"
+
+/* Note that primitive word definitions are compiled with
+__attribute__((regparm 2), so the pointer to the word object is passed in EAX,
+and the callstack top is passed in EDX */
+
+#define ARG0 %eax
+#define ARG1 %edx
+#define XT_REG %ecx
+#define STACK_REG %esp
+#define DS_REG %esi
+
+#define CELL_SIZE 4
+
+#define PUSH_NONVOLATILE \
+	push %ebx ; \
+	push %ebp
+
+#define POP_NONVOLATILE \
+	pop %ebp ; \
+	pop %ebx
+
+#define QUOT_XT_OFFSET 5
+#define PROFILING_OFFSET 25
+#define WORD_DEF_OFFSET 13
+#define WORD_XT_OFFSET 29
+
+/* We pass a function pointer to memcpy to work around a Mac OS X
+ABI limitation which would otherwise require us to do a bizzaro PC-relative
+trampoline to retrieve the function address */
+DEF(void,set_callstack,(F_STACK_FRAME *to, F_STACK_FRAME *from, CELL length, void *memcpy)):
+	mov 4(%esp),%ebp                   /* to */
+	mov 8(%esp),%edx                   /* from */
+	mov 12(%esp),%ecx                  /* length */
+	mov 16(%esp),%eax                  /* memcpy */
+	sub %ecx,%ebp                      /* compute new stack pointer */
+	mov %ebp,%esp
+	push %ecx                          /* pass length */
+	push %edx                          /* pass src */
+	push %ebp                          /* pass dst */
+	call *%eax                         /* call memcpy */
+	add $12,%esp                       /* pop args from the stack */
+	ret                                /* return _with new stack_ */
+
+#include "cpu-x86.S"
diff --git a/vm/cpu-x86.32.h b/vm/cpu-x86.32.h
new file mode 100644
index 0000000000..4c4acb0ad3
--- /dev/null
+++ b/vm/cpu-x86.32.h
@@ -0,0 +1,6 @@
+#define FACTOR_CPU_STRING "x86.32"
+
+register CELL ds asm("esi");
+register CELL rs asm("edi");
+
+#define FASTCALL __attribute__ ((regparm (2)))
diff --git a/vm/cpu-x86.64.S b/vm/cpu-x86.64.S
new file mode 100644
index 0000000000..1725c0cbd5
--- /dev/null
+++ b/vm/cpu-x86.64.S
@@ -0,0 +1,37 @@
+#include "asm.h"
+
+#define ARG0 %rdi
+#define ARG1 %rsi
+#define XT_REG %rcx
+#define STACK_REG %rsp
+#define DS_REG %r14
+
+#define CELL_SIZE 8
+
+#define PUSH_NONVOLATILE \
+	push %rbx ; \
+	push %rbp ; \
+	push %r12 ; \
+	push %r13 ;
+
+#define POP_NONVOLATILE \
+	pop %r13 ; \
+	pop %r12 ; \
+	pop %rbp ; \
+	pop %rbx
+
+#define QUOT_XT_OFFSET 13
+#define PROFILING_OFFSET 53
+#define WORD_DEF_OFFSET 29
+#define WORD_XT_OFFSET 61
+
+/* We pass a function pointer to memcpy to work around a Mac OS X
+ABI limitation which would otherwise require us to do a bizzaro PC-relative
+trampoline to retrieve the function address */
+DEF(void,set_callstack,(F_STACK_FRAME *to, F_STACK_FRAME *from, CELL length, void *memcpy)):
+	sub %rdx,%rdi                      /* compute new stack pointer */
+	mov %rdi,%rsp
+	call *%rcx                         /* call memcpy */
+	ret                                /* return _with new stack_ */
+
+#include "cpu-x86.S"
diff --git a/vm/cpu-x86.64.h b/vm/cpu-x86.64.h
new file mode 100644
index 0000000000..0b3b5a2471
--- /dev/null
+++ b/vm/cpu-x86.64.h
@@ -0,0 +1,6 @@
+#define FACTOR_CPU_STRING "x86.64"
+
+register CELL ds asm("r14");
+register CELL rs asm("r15");
+
+#define FASTCALL
diff --git a/vm/cpu-x86.S b/vm/cpu-x86.S
index aa64002898..3e2a97dd5c 100644
--- a/vm/cpu-x86.S
+++ b/vm/cpu-x86.S
@@ -1,83 +1,53 @@
-#include "asm.h"
-
-/* Note that primitive word definitions are compiled with
-__attribute__((regparm 2), so the pointer to the word object is passed in EAX,
-and the callstack top is passed in EDX */
-
-/* When calling a quotation, we pass the XT in ECX */
 #define JUMP_QUOT \
-	mov 5(%eax),%ecx ;                 /* Load quot-xt */ \
-	jmp *%ecx                          /* Jump to quot-xt */
+	mov QUOT_XT_OFFSET(ARG0),XT_REG ;     /* Load quot-xt */ \
+	jmp *XT_REG                           /* Jump to quot-xt */
 
-DEF(void,c_to_factor,(CELL quot)):
-	push %ebp                          /* Save non-volatile registers */
-	push %ebx
+DEF(FASTCALL void,c_to_factor,(CELL quot)):
+	PUSH_NONVOLATILE
+	push ARG0                             /* Save quot */
 
-	lea -8(%esp),%eax                  /* Save stack pointer */
-	push %eax                          /* This 16-byte aligns the stack */
+	lea -CELL_SIZE(STACK_REG),ARG0        /* Save stack pointer */
 	call MANGLE(save_callstack_bottom)
 
-	mov 16(%esp),%eax                  /* Pass quot as arg 1 */
-	mov 5(%eax),%ecx                   /* Pass quot-xt */
-	call *%ecx                         /* Call quot-xt */
+	mov (STACK_REG),ARG0                  /* Pass quot as arg 1 */
+	mov QUOT_XT_OFFSET(ARG0),XT_REG
+	call *XT_REG                          /* Call quot-xt */
 
-	pop %eax                           /* Clobber */
-	pop %ebx                           /* Restore non-volatile registers */
-	pop %ebp
+	POP ARG0
+	POP_NONVOLATILE
 	ret
 
-DEF(void,undefined,(CELL word)):
-	mov %esp,%ecx                      /* Save stack pointer before we mess with it */
-	sub $12,%esp                       /* Alignment */
-	mov %eax,4(%esp)                   /* Pass word as arg 1 (not fastcall) */
-	mov %ecx,8(%esp)                   /* Pass callstack pointer as arg 2 (not fastcall) */
-	jmp MANGLE(undefined_error)        /* This throws an error */
+DEF(FASTCALL void,undefined,(CELL word)):
+	mov STACK_REG,ARG1                    /* Pass callstack pointer */
+	jmp MANGLE(undefined_error)           /* This throws an error */
 
-DEF(void,dosym,(CELL word)):
-	add $4,%esi                        /* Increment stack pointer */
-	mov %eax,(%esi)                    /* Store word on stack */
+DEF(FASTCALL void,dosym,(CELL word)):
+	add $CELL_SIZE,DS_REG                 /* Increment stack pointer */
+	mov ARG0,(DS_REG)                     /* Store word on stack */
 	ret
 
 /* Here we have two entry points. The first one is taken when profiling is
 enabled */
-DEF(void,docol_profiling,(CELL word)):
-	add $8,25(%eax)                    /* Increment profile-count slot */
-DEF(void,docol,(CELL word)):
-	mov 13(%eax),%eax                  /* Load word-def slot */
+DEF(FASTCALL void,docol_profiling,(CELL word)):
+	add $CELL_SIZE,PROFILING_OFFSET(ARG0) /* Increment profile-count slot */
+DEF(FASTCALL void,docol,(CELL word)):
+	mov WORD_DEF_OFFSET(ARG0),ARG0        /* Load word-def slot */
 	JUMP_QUOT
 
 /* We must pass the XT to the quotation in ECX. */
-DEF(void,primitive_call,(void)):
-        mov (%esi),%eax                    /* Load quotation from data stack */
-	sub $4,%esi                        /* Pop data stack */
+DEF(FASTCALL void,primitive_call,(void)):
+        mov (DS_REG),ARG0                     /* Load quotation from data stack */
+	sub $CELL_SIZE,DS_REG                 /* Pop data stack */
 	JUMP_QUOT
 
 /* We pass the word in EAX and the XT in ECX. Don't mess up EDX, it's the
 callstack top parameter to primitives. */
-DEF(void,primitive_execute,(void)):
-	mov (%esi),%eax                    /* Load word from data stack */
-	sub $4,%esi                        /* Pop data stack */
-        mov 29(%eax),%ecx                  /* Load word-xt slot */
-	jmp *%ecx                          /* Go */
+DEF(FASTCALL void,primitive_execute,(void)):
+	mov (DS_REG),ARG0                     /* Load word from data stack */
+	sub $CELL_SIZE,DS_REG                 /* Pop data stack */
+        mov WORD_XT_OFFSET(ARG0),XT_REG       /* Load word-xt slot */
+	jmp *XT_REG                           /* Go */
 
-/* We pass a function pointer to memcpy in 16(%esp) to work around a Mac OS X
-ABI limitation which would otherwise require us to do a bizzaro PC-relative
-trampoline to retrieve the function address */
-DEF(void,set_callstack,(F_STACK_FRAME *to, F_STACK_FRAME *from, CELL length, void *memcpy)):
-	mov 4(%esp),%ebp                   /* to */
-	mov 8(%esp),%edx                   /* from */
-	mov 12(%esp),%ecx                  /* length */
-	mov 16(%esp),%eax                  /* memcpy */
-	sub %ecx,%ebp                      /* compute new stack pointer */
-	mov %ebp,%esp
-	push %ecx                          /* pass length */
-	push %edx                          /* pass src */
-	push %ebp                          /* pass dst */
-	call *%eax                         /* call memcpy */
-	add $12,%esp                       /* pop args from the stack */
-	ret                                /* return _with new stack_ */
-
-DEF(void,throw_impl,(CELL quot, F_STACK_FRAME *rewind_to)):
-	mov 4(%esp),%eax                   /* quot */
-	mov 8(%esp),%esp                   /* rewind_to */
+DEF(FASTCALL void,throw_impl,(CELL quot, F_STACK_FRAME *rewind_to)):
+	mov ARG1,STACK_REG                    /* rewind_to */
 	JUMP_QUOT
diff --git a/vm/cpu-x86.h b/vm/cpu-x86.h
index 3fc111729e..a535038eef 100644
--- a/vm/cpu-x86.h
+++ b/vm/cpu-x86.h
@@ -1,10 +1,3 @@
-#define FACTOR_CPU_STRING "x86.32"
-
-register CELL ds asm("esi");
-register CELL rs asm("edi");
-
-#define FASTCALL __attribute__ ((regparm (2)))
-
 typedef struct _F_STACK_FRAME
 {
 	/* In compiled quotation frames, position within the array.
@@ -29,14 +22,11 @@ typedef struct _F_STACK_FRAME
 
 INLINE void flush_icache(CELL start, CELL len) {}
 
-void c_to_factor(CELL quot);
+FASTCALL void c_to_factor(CELL quot);
+FASTCALL void throw_impl(CELL quot, F_STACK_FRAME *rewind_to);
+FASTCALL void undefined(CELL word);
+FASTCALL void dosym(CELL word);
+FASTCALL void docol_profiling(CELL word);
+FASTCALL void docol(CELL word);
 
 void set_callstack(F_STACK_FRAME *to, F_STACK_FRAME *from, CELL length, void *memcpy);
-void throw_impl(CELL quot, F_STACK_FRAME *rewind_to);
-
-/* Defined in cpu-x86.S and only called from Factor-compiled code. They all
-use funny calling convention. */
-void undefined(CELL word);
-void dosym(CELL word);
-void docol_profiling(CELL word);
-void docol(CELL word);
diff --git a/vm/image.c b/vm/image.c
index 0d1b22adee..32e628f902 100644
--- a/vm/image.c
+++ b/vm/image.c
@@ -81,19 +81,6 @@ void load_image(F_PARAMETERS *p)
 	userenv[IMAGE_ENV] = tag_object(from_native_string(p->image));
 }
 
-/* Compute total sum of sizes of free blocks */
-void save_code_heap(FILE *file)
-{
-	F_BLOCK *scan = first_block(&code_heap);
-
-	while(scan)
-	{
-		if(scan->status == B_ALLOCATED)
-			fwrite(scan,scan->size,1,file);
-		scan = next_block(&code_heap,scan);
-	}
-}
-
 /* Save the current image to disk */
 bool save_image(const F_CHAR *filename)
 {
@@ -132,7 +119,6 @@ bool save_image(const F_CHAR *filename)
 	fwrite(&h,sizeof(F_HEADER),1,file);
 
 	fwrite((void*)tenured->start,h.data_size,1,file);
-	/* save_code_heap(file); */
 	fwrite(first_block(&code_heap),h.code_size,1,file);
 
 	fclose(file);
@@ -187,6 +173,8 @@ void fixup_alien(F_ALIEN *d)
 	d->expired = T;
 }
 
+F_FIXNUM delta;
+
 void fixup_stack_frame(F_STACK_FRAME *frame)
 {
 	code_fixup(&frame->xt);
@@ -198,7 +186,21 @@ void fixup_stack_frame(F_STACK_FRAME *frame)
 		frame->scan = scan + frame->array;
 	}
 
-	/* code_fixup(&frame->return_address); */
+#ifdef CALLSTACK_UP_P
+	F_STACK_FRAME *next = REBASE_FRAME_SUCCESSOR(frame,delta);
+	code_fixup((XT *)(next + 1));
+#else
+	code_fixup(&frame->return_address);
+#endif
+}
+
+void fixup_callstack_object(F_CALLSTACK *stack)
+{
+	CELL top = (CELL)(stack + 1);
+	CELL bottom = top + untag_fixnum_fast(stack->length);
+	delta = (bottom - stack->bottom);
+
+	iterate_callstack_object(stack,fixup_stack_frame);
 }
 
 /* Initialize an object in a newly-loaded image */
@@ -221,9 +223,7 @@ void relocate_object(CELL relocating)
 		fixup_alien((F_ALIEN *)relocating);
 		break;
 	case CALLSTACK_TYPE:
-		iterate_callstack_object(
-			(F_CALLSTACK *)relocating,
-			fixup_stack_frame);
+		fixup_callstack_object((F_CALLSTACK *)relocating);
 		break;
 	}
 }
diff --git a/vm/layouts.h b/vm/layouts.h
index b924f61a81..e5419d1470 100644
--- a/vm/layouts.h
+++ b/vm/layouts.h
@@ -88,7 +88,7 @@ INLINE void *untag_object(CELL tagged)
 	return (void *)UNTAG(tagged);
 }
 
-typedef void (*XT)(CELL arg);
+typedef void *XT;
 
 /* Assembly code makes assumptions about the layout of this struct */
 typedef struct {
diff --git a/vm/os-freebsd-x86.32.h b/vm/os-freebsd-x86.32.h
new file mode 100644
index 0000000000..34299691bc
--- /dev/null
+++ b/vm/os-freebsd-x86.32.h
@@ -0,0 +1 @@
+#define UAP_PROGRAM_COUNTER(ucontext) (((ucontext_t *)(ucontext))->uc_mcontext.mc_eip)
diff --git a/vm/os-linux-x86-32.h b/vm/os-linux-x86-32.h
new file mode 100644
index 0000000000..e12133966d
--- /dev/null
+++ b/vm/os-linux-x86-32.h
@@ -0,0 +1,2 @@
+#define UAP_PROGRAM_COUNTER(ucontext) \
+	(((ucontext_t *)(ucontext))->uc_mcontext.gregs[14])
diff --git a/vm/os-linux-x86-64.h b/vm/os-linux-x86-64.h
new file mode 100644
index 0000000000..2bbae86f6e
--- /dev/null
+++ b/vm/os-linux-x86-64.h
@@ -0,0 +1,2 @@
+#define UAP_PROGRAM_COUNTER(ucontext) \
+	(((ucontext_t *)(ucontext))->uc_mcontext.gregs[16])
diff --git a/vm/os-macosx-x86.h b/vm/os-macosx-x86.32.h
similarity index 100%
rename from vm/os-macosx-x86.h
rename to vm/os-macosx-x86.32.h
diff --git a/vm/os-macosx.m b/vm/os-macosx.m
index e36d437cd6..07695b77fb 100644
--- a/vm/os-macosx.m
+++ b/vm/os-macosx.m
@@ -4,11 +4,11 @@
 
 void c_to_factor_toplevel(CELL quot)
 {
-	/* for(;;)
+	for(;;)
 	{
-NS_DURING */
+NS_DURING
 		c_to_factor(quot);
-		/* NS_VOIDRETURN;
+		NS_VOIDRETURN;
 NS_HANDLER
 		dpush(allot_alien(F,(CELL)localException));
 		quot = userenv[COCOA_EXCEPTION_ENV];
@@ -16,11 +16,11 @@ NS_HANDLER
 		{
 			/* No Cocoa exception handler was registered, so
 			extra/cocoa/ is not loaded. So we pass the exception
-			along. *
+			along. */
 			[localException raise];
 		}
 NS_ENDHANDLER
-	} */
+	}
 }
 
 void early_init(void)
diff --git a/vm/os-openbsd-x86.h b/vm/os-openbsd-x86.32.h
similarity index 100%
rename from vm/os-openbsd-x86.h
rename to vm/os-openbsd-x86.32.h
diff --git a/vm/os-openbsd-amd64.h b/vm/os-openbsd-x86.64.h
similarity index 100%
rename from vm/os-openbsd-amd64.h
rename to vm/os-openbsd-x86.64.h
diff --git a/vm/platform.h b/vm/platform.h
index 602c7e6af5..f181c93e2c 100644
--- a/vm/platform.h
+++ b/vm/platform.h
@@ -13,10 +13,8 @@
 #if defined(WINDOWS)
 	#if defined(WINCE)
 		#include "os-windows-ce.h"
-	#elif defined (__i386)
-		#include "os-windows-nt.h"
 	#else
-		#error "Unsupported Windows flavor"
+		#include "os-windows-nt.h"
 	#endif
 
 	#include "os-windows.h"
@@ -29,7 +27,7 @@
 		#include "mach_signal.h"
 		
 		#ifdef FACTOR_X86
-			#include "os-macosx-x86.h"
+			#include "os-macosx-x86.32.h"
 		#elif defined(FACTOR_PPC)
 			#include "os-macosx-ppc.h"
 		#else
@@ -44,7 +42,7 @@
 			#include "os-unix-ucontext.h"
 			
 			#if defined(FACTOR_X86)
-				#include "os-freebsd-x86.h"
+				#include "os-freebsd-x86.32.h"
 			#else
 				#error "Unsupported FreeBSD flavor"
 			#endif
@@ -53,9 +51,9 @@
 			#include "os-openbsd.h"
 
 			#if defined(FACTOR_X86)
-				#include "os-openbsd-x86.h"
+				#include "os-openbsd-x86.32.h"
 			#elif defined(FACTOR_AMD64)
-				#include "os-openbsd-amd64.h"
+				#include "os-openbsd-x86.64.h"
 			#else
 				#error "Unsupported OpenBSD flavor"
 			#endif
@@ -65,6 +63,7 @@
 
 			#if defined(FACTOR_X86)
 				#include "os-unix-ucontext.h"
+				#include "os-linux-x86-32.h"
 			#elif defined(FACTOR_PPC)
 				#include "os-unix-ucontext.h"
 				#include "os-linux-ppc.h"
@@ -72,6 +71,7 @@
 				#include "os-linux-arm.h"
 			#elif defined(FACTOR_AMD64)
 				#include "os-unix-ucontext.h"
+				#include "os-linux-x86-64.h"
 			#else
 				#error "Unsupported Linux flavor"
 			#endif
@@ -86,11 +86,13 @@
 #endif
 
 #if defined(FACTOR_X86)
+	#include "cpu-x86.32.h"
+	#include "cpu-x86.h"
+#elif defined(FACTOR_AMD64)
+	#include "cpu-x86.64.h"
 	#include "cpu-x86.h"
 #elif defined(FACTOR_PPC)
 	#include "cpu-ppc.h"
-#elif defined(FACTOR_AMD64)
-	#include "cpu-amd64.h"
 #elif defined(FACTOR_ARM)
 	#include "cpu-arm.h"
 #else
diff --git a/vm/run.c b/vm/run.c
index 2ed7bae7f4..2b946b0722 100644
--- a/vm/run.c
+++ b/vm/run.c
@@ -199,7 +199,7 @@ void not_implemented_error(void)
 }
 
 /* This function is called from the undefined function in cpu_*.S */
-void undefined_error(CELL word, F_STACK_FRAME *callstack_top)
+FASTCALL void undefined_error(CELL word, F_STACK_FRAME *callstack_top)
 {
 	stack_chain->callstack_top = callstack_top;
 	general_error(ERROR_UNDEFINED_WORD,word,F,NULL);
diff --git a/vm/run.h b/vm/run.h
index 732880ce97..4d031350d3 100644
--- a/vm/run.h
+++ b/vm/run.h
@@ -196,7 +196,8 @@ void memory_protection_error(CELL addr, F_STACK_FRAME *native_stack);
 void signal_error(int signal, F_STACK_FRAME *native_stack);
 void type_error(CELL type, CELL tagged);
 void not_implemented_error(void);
-void undefined_error(CELL word, F_STACK_FRAME *callstack_top);
+
+FASTCALL void undefined_error(CELL word, F_STACK_FRAME *callstack_top);
 
 DECLARE_PRIMITIVE(throw);
 
diff --git a/vm/stack.c b/vm/stack.c
index 9c36389b40..cf3c1df00a 100644
--- a/vm/stack.c
+++ b/vm/stack.c
@@ -19,7 +19,7 @@ void fix_stacks(void)
 }
 
 /* called before entry into Factor code. */
-void save_callstack_bottom(F_STACK_FRAME *callstack_bottom)
+FASTCALL void save_callstack_bottom(F_STACK_FRAME *callstack_bottom)
 {
 	stack_chain->callstack_bottom = callstack_bottom;
 }
@@ -111,7 +111,7 @@ void iterate_callstack(CELL top, CELL bottom, CELL base, CALLSTACK_ITER iterator
 
 	while(ITERATING_P)
 	{
-		F_STACK_FRAME *next = (F_STACK_FRAME *)((CELL)FRAME_SUCCESSOR(frame) + delta);
+		F_STACK_FRAME *next = REBASE_FRAME_SUCCESSOR(frame,delta);
 		iterator(frame);
 		frame = next;
 	}
@@ -344,7 +344,7 @@ static F_FIXNUM delta;
 
 void adjust_stack_frame(F_STACK_FRAME *frame)
 {
-	FRAME_SUCCESSOR(frame) = (F_STACK_FRAME *)((CELL)FRAME_SUCCESSOR(frame) + delta);
+	FRAME_SUCCESSOR(frame) = REBASE_FRAME_SUCCESSOR(frame,delta);
 }
 
 void adjust_callstack(F_CALLSTACK *stack, CELL bottom)
diff --git a/vm/stack.h b/vm/stack.h
index f07a1a76df..62ee1d9ba2 100644
--- a/vm/stack.h
+++ b/vm/stack.h
@@ -48,7 +48,7 @@ CELL ds_size, rs_size;
 void reset_datastack(void);
 void reset_retainstack(void);
 void fix_stacks(void);
-void save_callstack_bottom(F_STACK_FRAME *callstack_bottom);
+FASTCALL void save_callstack_bottom(F_STACK_FRAME *callstack_bottom);
 DLLEXPORT void save_stacks(void);
 DLLEXPORT void nest_stacks(void);
 DLLEXPORT void unnest_stacks(void);
@@ -56,6 +56,8 @@ void init_stacks(CELL ds_size, CELL rs_size);
 
 #define FIRST_STACK_FRAME(stack) (F_STACK_FRAME *)((stack) + 1)
 
+#define REBASE_FRAME_SUCCESSOR(frame,delta) (F_STACK_FRAME *)((CELL)FRAME_SUCCESSOR(frame) + delta)
+
 typedef void (*CALLSTACK_ITER)(F_STACK_FRAME *frame);
 
 void iterate_callstack(CELL top, CELL bottom, CELL base, CALLSTACK_ITER iterator);